Intracorporeal occlusive device and method

ABSTRACT

An intracorporeal space filling device and a delivery system and method for using the device is disclosed. The space filling device is preferably configured for percutaneous delivery from a peripheral conduit of a patient. The space filling device has an elongated tubular or interconnected bead structure which may have a transmutable material disposed within it. The transmutable material can be altered from a non-rigid state to a rigid state by the application of various types of energy or by other suitable means. The space filling device can be positioned by a delivery system and detached from the delivery system after desired positioning is achieved.

This application is a continuation of application Ser. No. 11/169,322,filed Jun. 28, 2005, which is a continuation of application Ser. No.11/033,463, filed Jan. 11, 2005, which is a continuation of applicationSer. No. 10/106,511, filed Mar. 25, 2002 which is a divisionalapplication of application Ser. No. 09/324,987, filed Jun. 2, 1999. Thedisclosures of these prior applications are incorporated in theirentirety herein by this reference.

BACKGROUND

The present invention is generally directed to occlusion devices and,more specifically, to intracorporeal occlusion devices which can be usedto treat a patent's blood vessels, intracorporeal conduits or otherportions of a patient's body. A preferred embodiment can be used totreat intracranial aneurysms, arteriovenous fistulas, and otherabnormalities within the cerebral vasculature.

Cerebral aneurysms and other cerebral vascular abnormalities present asignificant medical problem to the population of the United States. Itis estimated that the number of ruptured intracranial aneurysms yearlyis in the tens of thousands, often with devastating consequences for thepatient. For a patient who has been diagnosed with a cerebral aneurysm,there are a few treatment modalities currently available. An invasivesurgical treatment can be used where access to the external portion ofthe aneurysm is achieved by placing the patient under generalanesthesia, performing a craniotomy, and brain tissue retraction. Onceaccess has been gained to the external surface of the aneurysm, the neckof the aneurysm can be clipped. Clipping the aneurysm neck prevents theingress of blood into the aneurysm cavity which can lead to rupture.Because of the invasive nature of the procedure and the vulnerability ofthe brain tissue surrounding the aneurysm, this procedure carries a highdegree of risk with concomitant mortality and morbidity rates. This riskis particularly high when the aneurysm has ruptured prior to thesurgical intervention.

An alternative to the surgical method currently in use involvespercutaneous endovascular intervention. This method generally involvesaccessing the cerebral aneurysm by means of an intravascularmicrocatheter which is advanced under flouroscopic imaging over aguidewire or the like within the patient's arteries from a puncture sitein the patient's leg or arm. The distal end of the microcatheter isguided over a guidewire within a patient's vasculature and disposedadjacent the neck of the aneurysm. The distal tip of the microcathetercan then be directed into the cavity of the aneurysm and appropriateocclusive devices then delivered from a port in the distal end of themicrocatheter. Presently, the most common occlusive device delivered viamicrocatheter is a vaso-occlusive coil which consists of stainless steelor radiopaque metals such as gold or platinum, tantalum. Thevaso-occlusive coils are typically manufactured in a manner similar tothe distal coils of a coronary guidewire, having a coil wire materialwith a small diameter and a coil outer diameter suitable for deliverythrough a microcatheter. Such vaso-occlusive coils are often given asecondary shape or configuration whereby the coils can be straightenedand delivered through the inner lumen of a microcatheter, but form aconvoluted or random space filling structure once delivered from thedistal end of the microcatheter. The endovascular delivery ofvaso-occlusive coils through a microcatheter represents a significantadvance in treating cranial aneurysms. However, the coils are hollowbodies, often made of relatively soft metals which are subject tocompaction due to the pressure exerted on the deployed coils by thepatient's blood flow. Compaction and reforming of the coils leaves themsusceptible to dislodging and being displaced within the patient'svasculature, with the potential for causing distal embolization. Inaddition, compaction of the coils into the dome of the aneurysm or bloodclot surrounding the coils can lead to reappearance and regrowth of theaneurysm. Finally, aneurysms with wide necks having a dome to neckdimension ratio of less than 2 to 1 often do not provide a morphologyconducive to retention of coils within the aneurysm. Thus currentlyavailable coils are generally contraindicated for use in wide neckaneurysms. What has been needed is an intracorporeal space fillingdevice which can be delivered by non-invasive methods, is not subject tocompaction or reforming and which is suitable for implantation in wideneck aneurysms.

SUMMARY

The invention is directed generally to an intracorporeal space fillingdevice and a delivery system for positioning and deploying the spacefilling device within a patient. The invention is also directed to amethod for using the space filling device.

One preferred embodiment of the invention is an intracorporeal spacefilling device which has an elongate tubular shell with a lumen disposedwithin the shell. The lumen is in fluid communication with a first portin a first end of the shell, and a second port in a second end of theshell. A transmutable material is disposed within the lumen of the shellsubstantially filling the lumen. The transmutable material hasproperties which enable transformation from a non-rigid state to asubstantially rigid state within a patient's body. The transmutablecharacter of the transmutable material allows for a space filling devicethat is soft and flexible at the time of deployment into anintracorporeal cavity and rigid and substantially incompressible afterbeing converted to a rigid state. Such a device can conform readily tothe varied morphology of intracorporeal cavities and transmute to asubstantially rigid mass upon activation or hardening of thetransmutable material so as to be resistant to compression and reformingdue to vascular or other types of pressures within a patient's body.

The elongate shell is generally made of a polymeric wall material and issealed at either or both of the first and second ends. The transmutablematerial which fills the lumen of the shell can be selected from avariety of suitable polymers which can be made rigid or hardened by theapplication of a variety of energy types such as light emitted from alaser or other source, radiofrequency energy, ultrasonic energy or othersuitable means such as controlled changes in the pH of the materialsurrounding the transmutable material. The space filling device istypically configured for percutaneous delivery through a suitablemicrocatheter from an incision in a peripheral artery in a patient's armor leg to a desired intracorporeal cavity, such as a cerebral aneurysm.

Optionally, the space filling device may have an elongated longitudinalmember secured to and preferably coextensive with the elongate tubularshell of the device. Typically, the elongated longitudinal member is athin wire member that may or may not be configured to give a secondaryshape to the space filling device when in an unconstrained relaxedstate. The secondary shape of the longitudinal member can be aconvoluted, folded, coiled or twisted configuration or any othersuitable space filling configuration when in an unconstrained statewhich is imparted to the intracorporeal space filling device to whichthe elongated longitudinal member is secured. When the device is in alinear constrained state or configuration, it may be advanced through aninner lumen of a microcatheter or other similar device for delivery to adesired site within a patient's body. Once the space filling device isremoved from the constraint of the microcatheter, it again assumes thespace filling secondary shape. The elongated longitudinal member can bemade from a variety of suitable materials, including stainless steel andshape memory alloys such as nickel titanium (NiTi). The elongatedlongitudinal member can be disposed along a longitudinal axis of thespace filling device, embedded in the transmutable material,encapsulated within the wall material of the elongate tubular shell, oradjacent an outside surface of the elongate tubular shell or any othersuitable location on the device. Preferably the elongate longitudinalmember is substantially parallel to the longitudinal axis of theelongate shell or intracorporeal space filling device. The elongatedlongitudinal member can also be configured to be heated by the passageof various types of energy therethrough. For example, an elongatedlongitudinal member made of NiTi alloy can be configured to be heated bythe passage of electrical current, including radiofrequency, orultrasonic energy through it. Heating of the elongated longitudinalmember can be used to transmute or rigidify the transmutable materialwithin the elongate shell and to act as a mechanism for detachment ofthe intracorporeal space filling device from the distal end of thedelivery system.

In a preferred embodiment, the elongate tubular shell is configured tohave an outer surface which is self adhering to create attachment pointsfrom contact point upon activation of the self adhering outer surface.Contact points along the length of the space filling device inevitablyoccur when the device is deployed within an intracorporeal cavity orchannel and the space filling device assumes a folded or convolutedspace filling configuration. The folded or convoluted space fillingconfiguration may be due to the confinement of the void or channel, asecondary shape assumed by the device in a relaxed state, or both. Thecreation of attachment points results in a more rigid and stable spacefilling mass that is resistant to compaction and reforming.

The intracorporeal space filling device may optionally have a helicalcoil disposed about an outer surface of the elongate tubular shell. Thehelical coil may have properties similar to those discussed above withregard to the elongated longitudinal member. For example, the helicalcoil can be configured to impose a convoluted, folded or space fillingsecondary shape on the space filling device when in a relaxedunconstrained state. The helical coil may also be configured to heat orotherwise activate transmutation of the transmutable material whenvarious forms of energy are passed through it such as electricalcurrent, ultrasonic energy or the like. The materials of the helicalcoil may also be similar to those discussed above with regard to theelongated longitudinal member.

In an alternative embodiment, the space filling device has atransmutable material disposed about an elongated longitudinal memberwithout an outer shell so that the transmutable material is exposed whenthe device is deployed within a patient's body. The elongatedlongitudinal member can have properties similar to those of theelongated longitudinal members discussed above. For example, theelongated longitudinal member can be made of a thin wire with asecondary shape. The secondary shape can be imparted on the spacefilling device when the device is in an unconstrained state. Secondaryshapes can include convoluted or folded space filling configurations.Exposure of an outside surface of the transmutable material allows thetransmutable material to adhere to itself upon transmutation atattachment points where different portions of the space filling devicemake contact due to the secondary shape assumed. When the space fillingdevice is deployed in an intracorporeal cavity and assumes a folded,bunched or convoluted configuration due to a secondary shape of theelongated longitudinal member or the natural confinement of the cavity,inevitably, certain portions of the space filling device will makephysical contact with other portions of the device. As such, thetransmutable material of these portions will make contact at contactpoints and will cross-link, bond, or self adhere to each other to formattachment points upon transmutation of the transmutable material. Thecross-linking or bonding of the device at attachment points results in arigid mass which is resistive to compression and reforming. The selfadhering property of the outside surface of the transmutable materialcan be as a result of the intrinsic properties of the transmutablematerial, or as a result of a coating applied to the transmutablematerial with self adhering properties.

In another embodiment, the intracorporeal space filling device has aplurality of beads connected to at least one adjacent bead by a flexiblemember with connections to adjacent beads being configured to produce alinear array of the beads. Each bead has a transverse dimension and isgenerally spaced within one transverse dimension of adjacent beads,however, other appropriate spacings are possible. The space fillingdevice of interconnected beads is generally configured for percutaneousdelivery through a microcatheter or the like from an incision in aperipheral artery of a patient to a desired cavity within the patient'svasculature such as a cerebral aneurysm. The individual beads typicallyhave a generally spherical shape, but can also be substantiallyelliptical or elongated. The beads can be made from any suitablematerial, but are preferably made from a polymer material, and morepreferably a transmutable polymer material. In a particular embodiment,the beads may have an outer shell which defines a cavity whichoptionally contains suitable filler material. Suitable filler materialsinclude biocompatible fluids such as a saline, silicone and the like,and polymers such as a transmutable material similar to the transmutablematerial discussed above.

Embodiments with beads of exposed transmutable material can becross-linked or bonded to adjacent beads which are in contact at thetime of transmutation at a desired site within a patient's body.Adjacent beads in contact while deployed within a desired locationwithin a patient can adhere or bond together and create attachmentpoints upon transmutation of the transmutable material. The attachmentpoints create a more stable and rigid mass than would be achieved bytransmutation of the beads without attachment points.

The flexible member connecting adjacent beads may consist ofinterconnected portions of a polymer wall material of the outer shell ofeach adjacent bead. The flexible member may also be an elongatedlongitudinal member disposed substantially along a longitudinal axis ofthe space filling device and being substantially coextensive with atleast two adjacent beads of the space filling device. In embodiments ofthe space filling device having a flexible member consisting of anelongated longitudinal member, the elongated longitudinal member may bea thin wire, preferably of a shape memory alloy. The thin wirelongitudinal member can be configured to be heated by a passage ofenergy through it in order to activate transmutation of transmutablematerial disposed thereon. The elongated longitudinal member may also beconfigured to have a secondary shape or space filling configuration in arelaxed state as discussed above with regard to other elongatedlongitudinal members. The secondary shape or space filling configurationof the elongated longitudinal member would be imparted to the spacefilling device as a whole when in an unconstrained relaxed state.

The intracorporeal space filling devices discussed above are generallydeployed at a desired site within a patients body by disposing thedistal end of a microcatheter or the like such that a distal port in thedistal end of the microcatheter is directed to a desired cavity orchannel within a patient. The space filling device is then distallyadvanced within the inner lumen of the microcatheter, preferably bymeans of a delivery system which has an elongate shaft with a detachmentmechanism disposed on the distal end of the system. The detachmentmechanism is detachably secured to a first end of the space fillingdevice which provides a detachable connection and allows for remoteadvancement and retraction of the space filling device within thepatient prior to detachment. The space filling device is then distallyadvanced out of a port in the distal end of the microcatheter and intothe cavity or channel of the patient. When the space filling device isappropriately positioned, the transmutable material within the device isactivated so as to be hardened or rigidified, and the device detachedfrom the delivery system. Preferably, the space filling device isdetached by a detachment mechanism utilizing degradation of a polymerlink between the delivery system and the first end of the space fillingdevice. Degradation of the polymer link may be accomplished by a chaincleavage reaction which can be initiated by heating of the polymer link.Alternative detachment mechanisms include mechanical detachment,electrolytic detachment, detachment by shape memory alloy or shapememory polymer activation via application of RF energy, laser energy orultrasonic energy, heating of a hot melt adhesive joint, ultrasonic linkdegradation, hydrokinetic pressure activation of a mechanical retentiondevice, and the like.

During deployment of a space filling device, a blocking balloon may bedeployed adjacent the opening of an intracorporeal void and distal endof a microcatheter disposed within the void prior to distally advancingthe space filling device from the distal end of the microcatheter intothe cavity. The blocking balloon prevents egress of the space fillingdevice from within the cavity during deployment of the device.

These and other advantages of the invention will become more apparentfrom the following detailed description of the invention when taken inconjunction with the accompanying exemplary drawings.

BRIEF DESCRIPTION

FIG. 1 is a longitudinal sectional view of an intracorporeal spacefilling device having features of the invention.

FIG. 2 is a transverse cross sectional view of the intracorporeal spacefilling device of FIG. 1 taken at lines 2-2 of FIG. 1.

FIG. 3 is a longitudinal sectional view of an intracorporeal spacefilling device having features of the invention.

FIG. 4 is a transverse cross sectional view of the intracorporeal spacefilling device of FIG. 3 taken at lines 44 of FIG. 3.

FIG. 5 is a longitudinal sectional view of an intracorporeal spacefilling device having features of the invention.

FIG. 6 is a transverse cross sectional view of the intracorporeal spacefilling device of FIG. 5 taken at lines 6-6 of FIG. 5.

FIG. 7 is a longitudinal sectional view in of an intracorporeal spacefilling device similar to the device of FIG. 1, but including an outercoil member.

FIG. 8 is a transverse cross sectional view of the device of FIG. 7taken along lines 8-8 in FIG. 7.

FIG. 9 is a longitudinal sectional view of an intracorporeal spacefilling device having features of the invention.

FIG. 10 is a transverse cross sectional view of the intracorporeal spacefilling device of FIG. 9 taken at lines 10-11 of FIG. 9.

FIG. 11 is a transverse cross sectional view of the intracorporeal spacefilling device of FIG. 9 taken at lines 11-11 of FIG. 9.

FIG. 12 is a longitudinal sectional view of an intracorporeal spacefilling device having features of the invention.

FIG. 13 is a transverse cross sectional view of the intracorporeal spacefilling device of FIG. 12 taken at lines 13-13 of FIG. 12.

FIG. 14 is a longitudinal sectional view of an intracorporeal spacefilling device having features of the invention.

FIG. 15 is a transverse cross sectional view of the intracorporeal spacefilling device of FIG. 14 taken at lines 15-15 of FIG. 14.

FIG. 16 is a schematic view in partial longitudinal section of amicrocatheter over a guidewire disposed within a patient's blood vessel.

FIG. 17 is a schematic view in partial section of the distal end of amicrocatheter disposed within the neck of an aneurysm.

FIG. 18 is a schematic view in partial section of the distal end of amicrocatheter disposed within an aneurysmal cavity with anintracorporeal space filling device deployed within the aneurysm.

FIG. 19 is a schematic view in partial section of a blocking balloondeployed adjacent an aneurysm with the distal end of a microcatheterdisposed within the aneurysm and an intracorporeal space filling devicedisposed within the aneurysm.

FIG. 20 is an elevational view in partial section of a first end of anintracorporeal space filling device detachably secured to a distal endof a delivery system having features of the invention.

FIG. 21 is an elevational view in partial section of a first end of anintracorporeal space filling device detachably secured to a distal endof a delivery system having features of the invention.

FIG. 22 is an elevational view in partial section of a first end of anintracorporeal space filling device detachably secured to a distal endof a delivery system having features of the invention.

FIG. 23 is an elevational view in partial section of a first end of anintracorporeal space filling device-detachably secured to a distal endof a delivery system having features of the invention.

FIGS. 24-26 depict an alternative embodiment of a capture element fordetachment of the space filling device.

FIG. 27 is a longitudinal sectional view of an alternate embodiment ofthe device of FIG. 1 further including apertures.

FIG. 28 is a cross sectional view of the device of FIG. 27.

FIG. 29 is a longitudinal sectional view of an another embodimentsimilar to the device of FIG. 3 further including apertures.

FIG. 30 is a cross sectional view of the device of FIG. 29 taken alongline 30-30.

FIG. 31 is a longitudinal sectional view of an another embodimentsimilar to the device of FIG. 9 further including apertures.

FIG. 32 is a cross sectional view of the device of FIG. 30 taken alongline 32-32.

FIG. 33 is a cross sectional view of the device of FIG. 30 taken alongline 33-33.

DETAILED DESCRIPTION

FIG. 1 illustrates an intracorporeal space filling device 10 havingfeatures of the invention. The intracorporeal space filling device 10has an optional elongate tubular shell 11 with a first end 12 and asecond end 13, the elongate shell being formed of a wall material 14.There is a lumen 15 disposed within the elongate tubular shell 11 whichhas transmutable material 16 disposed therein.

The elongate tubular shell 11 can be made from a variety of materialsincluding metals and polymers. Suitable metals for the elongate tubularshell include stainless steel, NiTi, gold, platinum, tantalum,palladium, alloys thereof and the like. If a metal or other rigidmaterial is used, methods such as forming slots or grooves in the wallmaterial of such an elongate tubular shell may be used to achieve adesired longitudinal flexibility of the elongate tubular shell 11.Suitable polymers for the elongate tubular shell 11 can includepolyurethane, polyethylene, nylon, polyimide, polyamide,polytetraflouroethylene, polyester, polypropylene and the like. Theelongate tubular shell 11 may be sealed and impermeable to thetransmutable material 16, so as to prevent the egress of thetransmutable material from within the shell to the surroundingenvironment.

In one preferred embodiment features of which are depicted in FIGS. 27and 28, the elongate tubular shell 11 has at least one aperture 200which exposes the transmutable material 16 and allows thetransmutable-material to make contact with adjacent portions of thespace filling device or other space filling devices so as to permit selfadhering or bonding upon transmutation of the transmutable material. Theapertures in the elongate tubular shell 11 can be in the form oftransverse or longitudinal slots or grooves, circular or otherwiseconfigured holes, or the like. The apertures may be relatively far apartrelative to the size of the apertures, or they may be relatively closetogether and numerous so as to form a mesh pattern or other suitablepattern of fenestration which facilitates exposure of the transmutablematerial 16 but maintains the overall elongated structure of the spacefilling device 10. Similar apertures may be appropriate for any of thevarious embodiments of space filling devices discussed herein havingouter shell structures.

The dimensions of the space filling device 10 and elongate tubular shell11 are generally appropriate for percutaneous delivery via amicrocatheter to a desired site within a patient's vasculature, however,other suitable dimensions and configurations are contemplated. Thelength of the space filling device 10, and all other embodiments ofspace filling devices discussed herein generally, can be from about 0.5to about 50 cm, preferably about 2 to about 30 cm. It should be notedthat the morphology of the sites being filled or otherwise treated bythe present invention vary greatly. Embodiments of the invention for usetreating cerebral aneurysms may be made available in a variety of sizesand lengths so that most of the anticipated morphologies can beaccommodated. For example, a space filling device 10, and other spacefilling devices discussed herein generally, configured for treatment ofcerebral aneurysms, or the like, may be made available in lengths of 2,5, 10, 15, 20, 25, 30, 35 and 40 cm. In this way, a wide range ofaneurysm volumes can be appropriately treated.

A transverse dimension of the space filling device 10, and of all otherembodiments of space filling device discussed herein generally, can befrom about 0.005 to about 0.25 inches, preferably about 0.01 to about0.038 inches, and more preferably about 0.014 to about 0.018 inches. Inother preferred embodiments of the invention, the transverse dimensionof the space filling device can be from about 0.004 to about 0.02inches, preferably about 0.008 to about 0.012 inches. The thickness ofthe wall material 14 of the elongate tubular shell 11 can be from about0.0001 to about 0.01 inches, preferably about 0.0005 to about 0.002inches, and more preferably about 0.001 to about 0.0015 inches.

The transmutable material 16 disposed within the elongate tubular shell11 is preferably a material that can be transmuted by polymerization,crystallization or other suitable process from a non-rigid liquid, gelor granular state to a rigid state. Some of the materials suitable forthis application are discussed generally in U.S. Pat. No. 5,334,201, K.Cowan, and U.S. Pat. No. 5,443,495, P. Buscemi, et al., which are herebyincorporated by reference in their entirety. Transmutation of thetransmutable material can be achieved or activated by the application ofa suitable type of energy to the transmutable material. Suitable typesof energy include electromagnetic energy in the form of light, DCcurrent, AC current, RF current or the like in addition to ultrasonicenergy. Energy may also be applied directly or indirectly in the form ofheat to cause transmutation. Transmutation may also be activated byaltering the chemistry of the environment surrounding the transmutablematerial such as by changing the pH or by injection of a catalyst intothe transmutable materials, either directly or indirectly by injectionor introduction into the surrounding tissue or bodily fluid such ablood. With regard to the embodiment of FIG. 1, laser or RF energy ispreferably applied to the outer surface of the elongate tubular shelland transmutable material to cause transmutation. The outer dimensionsof the transmutable material 16 are generally similar to the cavitydimensions of the elongate tubular shell 11. As an alternative to thetransmutable material 16, any suitable biocompatible filler material maybe used such as saline, silicone or the like. Such alternative fillermaterials may be used within any of the suitable embodiments of spacefilling devices described herein, either as an alternative to atransmutable material, or in addition to a transmutable material.Embodiments of the invention suitable for alternative filler materialsare generally those embodiments having a shell structure configured toconfine the alternative filler materials.

In embodiments of the space filling device 10 where the transmutablematerial 16 is exposed, that is, where the optional elongate tubularshell 11 is not present, or portions of the elongate tubular shell 11are not present at aperture sites, it is preferable that thetransmutable material 16 be self adhering in a fluid field, such asblood or saline. In this way, when the device 10 is deployed within anintracorporeal cavity or channel and folds back on itself as a result ofthe confinement of the cavity or channel, any contact points betweentransmutable material where the device is folded on itself and makingmechanical contact will become attachment points upon transmutation ofthe transmutable material by bonding or adhering to itself at thecontact points. The attachment points result in a more stable spacefilling mass that is resistant to compaction and reforming.

Suitable substances generally for the transmutable material 16 includemethacrylate compounds, linear polyester, silicone, cyanoacrylates,polyisocyanate, u.v. curable acrylates, moisture cure silicones,dimethyl sulfoxide, thioisocyanate aldehyde, isocyanate, divinylcompounds, epoxide acrylates, succinimidyl azido salicylate,succinimidyl azidobenzoate, succinimidyl dithio acetate,azidoiodobenzene, flouronitrophenylazide, salicylate azides,benzophenonemaleimide, and the like.

FIG. 2 is a transverse cross sectional view of the intracorporeal spacefilling device 10 of FIG. 1. The transmutable material 16 is disposedwithin the optional elongate tubular shell 11 of the device. The crosssection of FIG. 2 is shown as substantially round, however, othersuitable cross sectional configurations can be used such as elliptical,triangular or square.

FIGS. 3 and 4 illustrate an intracorporeal space filling device 20similar to the embodiment of FIG. 1, with the addition of an elongatedlongitudinal member 21 disposed along a longitudinal axis 22 of theoptional elongate tubular shell 23. The materials, dimensions, andfeatures of the elongated tubular shell 23 of FIGS. 3 and 4 can besimilar to those of the elongated tubular shell 11 of FIGS. 1 and 2. Thematerials and dimensions of the transmutable material 24 can be similarto those of the transmutable material 16 discussed above. Typically, theelongated longitudinal member 21 is a thin wire member that isconfigured to give a secondary shape to the space filling device when inan unconstrained relaxed state. The longitudinal member 21 can have asecondary shape of a convoluted, folded, coiled or twisted configurationor any other suitable space filling configuration when in anunconstrained state. This configuration is imparted to theintracorporeal space filling device 20 to which the elongatedlongitudinal member 21 is secured. When the device 20 is in a linearconstrained state or configuration, it may be advanced through an innerlumen of a microcatheter or other similar device for delivery to adesired site within a patients body. Once the space filling device 20 isremoved from the constraint of the microcatheter, it again assumes thespace filling configuration. The space filling device 20, and all otherspace filling devices described herein generally which are configured tohave a secondary space filling shape, may have a variety of nominaltransverse dimensions or diameters when in a secondary shape. In orderto conform to a wide variety of intracorporeal morphologies, the spacefilling device may have a secondary shape with a transverse dimension ofbetween about 1 to about 20 mm. A typical space filling device maybemade with a secondary shape having a transverse dimension of between 1and 20 mm, in 1 mm increments.

The elongated longitudinal member 21 can be made from a variety ofsuitable materials, including stainless steel and shape memory alloyssuch as nickel titanium (NiTi). The length of the elongated longitudinalmember 21 can be from about 0.5 to about 50 cm, preferably about 1 toabout 20 cm, and more preferably about 5 to about 15 cm. It ispreferable that the elongated longitudinal member 21 be coextensive withthe length of the elongated tubular shell 23 and with the space fillingdevice generally. Thus, the elongated longitudinal member may have anyof the lengths discussed herein with regard to space filling devices.The transverse dimension of the elongated longitudinal member 21 can befrom about 0.0005 to about 0.01 inches, preferably about 0.001 to about0.003 inches, and more preferably about 0.0015 to about 0.002 inches.The cross section of the elongated longitudinal member is generallyround, however, other configurations are contemplated. Alternative crosssectional shapes for the elongated longitudinal member includeelliptical, rectangular, as would be found if a flat ribbon wire used,triangular, square and the like. The various cross sections can bechosen to give a desired preferred bend axis or axes along the length ofthe member. Preferably the elongate longitudinal member is substantiallyparallel to the longitudinal axis 22 of the elongate shell orintracorporeal space filling device. The elongated longitudinal member21 can also be configured to be heated by the passage of various typesof energy therethrough. For example, an elongated longitudinal member 21made of NiTi alloy can be configured to be heated by the passage ofelectrical current through it. Heating of the elongated longitudinalmember 21 can be used to transmute or rigidify the transmutable materialwithin the elongate tubular shell 23 and to act as a mechanism fordetachment of the intracorporeal space filling device 20 from a distalend of a delivery system. In an alternate embodiment, the shell 23includes apertures 200 for exposing the transmutable material, asdescribed in reference to FIGS. 27 and 28.

FIGS. 5 and 6 show an embodiment of an intracorporeal space fillingdevice 30 similar to the embodiment of FIGS. 3 and 4 but having anelongated longitudinal member 31 encapsulated within a wall material 32of the elongated tubular shell 33. The materials, dimensions andfeatures of the elongated tubular shell 33 and elongated longitudinalmember 31 of FIGS. 5 and 6 are similar to those of the elongated tubularshell 23 and elongated longitudinal member 21 of FIGS. 3 and 4. Theelongated longitudinal member 31 may also be secured to an outsidesurface 34 or inside surface 36 of the elongate tubular shell 33 by anadhesive or other suitable means. A transmutable material 35 disposedwithin the elongate tubular shell 33 can have properties and dimensionssimilar to or the same as those of transmutable materials 16 and 24 ofFIGS. 1-4 above.

FIGS. 7 and 8 illustrate an intracorporeal space filling device 40similar to that of FIGS. 1 and 2, but with a helical coil 41 disposedabout an outside surface 42 of the elongated tubular shell 43. Thehelical coil 41 of FIGS. 7 and 8 may have some properties similar tothose discussed above with regard to the elongated longitudinal members21 and 31 of FIGS. 3-6. The helical coil 41 can be configured to imposea convoluted, folded or space filling configuration on the space fillingdevice 40 when in a relaxed unconstrained state. The helical coil 41 mayalso be configured to heat when various forms of energy are passedthrough it. The materials of the helical coil 41 can be any suitablemetal, composite or polymer including shape memory alloys such as NiTior high strength alloys such as stainless steel. The type and dimensionsof the material from which the helical coil 41 is made can be similar tothe elongated longitudinal member 31 discussed above. A transmutablematerial 44 is disposed within the elongated tubular shell 43 and canhave properties similar or identical to the properties of transmutablematerials 16, 24 and 35 of FIGS. 1-6 above.

FIGS. 9-11 depict an alternative embodiment of an intracorporeal spacefilling device 50 having a plurality of beads 51 secured to each otherin a linear configuration. The intracorporeal space filling device 50has a plurality of beads 51 connected to at least one adjacent bead by aflexible member 52 with connections to adjacent beads preferably beingconfigured to produce a linear array of the beads. Each bead 51 has atransverse dimension and is generally spaced within one transversedimension of adjacent beads, however, other appropriate spacings arepossible. The space filling device 50 is generally configured forprecutaneous delivery through a microcatheter or the like from anincision in a peripheral artery of a patient to a desired cavity withinthe patient's vasculature such as a cerebral aneurysm. The individualbeads 51 typically have a generally spherical shape, but can also besubstantially elliptical, with the elliptical shape optionally beingelongated longitudinally to a length of multiple transverse dimensions.The beads 51 can be made from a rigid homogeneous polymer material, butare preferable made from an outer shell 53 which defines a cavity 54such as is shown in FIGS. 9-11. The outer shell 53 can be made from avariety of materials including metals and polymers. Suitable metals forthe shell 53 include stainless steel, NiTi, gold, platinum, tantalum,palladium, alloys thereof and the like. If a metal or other rigidmaterial is used, methods such as forming slots or grooves in the wallmaterial of the shell may be used to achieve a desired longitudinalflexibility. Suitable polymers for the shell 53 can includepolypropylene and the like. The outer shell 53 as shown in FIGS. 31-33may have apertures 203 similar to those of space filling device 10described above for exposing portions of transmutable material containedtherein which facilitates self adherence and the creation of attachmentpoints upon transmutation of the transmutable material.

The cavity 54 optionally contains a transmutable material 55 similar tothe transmutable materials 16, 24, 35 and 44 discussed above. Thetransmutable material 55 is preferably a material that can be transmutedby polymerization, crystallization or other suitable process from anon-rigid liquid, gel or granular state to a rigid state. Transmutationof the transmutable material 55 can be achieved or precipitated by theapplication of a suitable type of energy to the transmutable materialsuch as electromagnetic energy in the form of light, DC current, ACcurrent, RF or ultrasonic energy. Energy may also be applied directly orindirectly in the form of heat to cause transmutation. Other methods ofcausing or precipitating transmutation can include altering the pH ofthe surrounding environment of the transmutable material, or injecting acatalyst into the transmutable material directly, or indirectly byinjecting a catalyst into the environment of the transmutable material.

The dimensions of the space filling device 50 overall are similar tothose of the previously discussed embodiments. The thickness of the wallmaterial 56 of the outer shell 53 can be from about 0.0001 to about 0.01inches, preferably about 0.0005 to about 0.002 inches, and morepreferably about 0.001 to about 0.0015 inches. The wall material 56 ofthe outer shell 53 of the beads 51 and the transmutable material 55disposed within the outer shell can be similar to the materials of theelongate tubular shell 11 and transmutable material 16 of the embodimentof FIG. 1.

The flexible member 52 connecting adjacent beads may consist ofinterconnected portions of a polymer wall material 56 of the outer shell53 of each adjacent bead as shown in FIGS. 9-11. As shown in FIGS.12-13, an intracorporeal space filling device 60 may have flexiblemembers 61 that consist of portions of an elongated longitudinal member62 disposed substantially along a longitudinal axis 63 of the spacefilling device 60 and being substantially coextensive with at least twoadjacent beads 64 of the space filling device. The beads 64 of the spacefilling device 60 are made of a polymer material 65 which is atransmutable material. The exposed outer surface of the transmutablematerial of the beads 64 is self adhering in a fluid field, such asblood or saline. When the space filling device 60 is deployed within abody cavity and folds back on itself as a result of the confinement orsecondary shape, any contact points where the device is folded on itselfmaking mechanical contact will become attachment points upontransmutation of the transmutable material of the beads 64. Theattachment points result in a more stable space filling mass which isresistant to compaction and reforming.

The elongated longitudinal member 62 may be a thin wire, preferably of ashape memory alloy that can be configured to be heated by a passage ofenergy through it. The elongated longitudinal member 62 shown in FIGS.12-13 can have similar dimensions and properties to the elongatedlongitudinal members 21 and 31 shown in FIGS. 3-6. These properties caninclude a secondary shape, shape memory properties, and heating upon apassage of energy through the elongate longitudinal member 62. Inaddition, the elongated longitudinal member 62 can have a variety ofcross section configuration including round, square, rectangular and thelike.

FIGS. 14 and 15 depict an intracorporeal space filling device 66 whichhas beads 67 attached in a substantially linear array by an elongatelongitudinal member 68. The beads 67 have an outer shell 69 which isoptionally filled with a transmutable material 69A. The dimensions andmaterials of beads 67 can be similar to those of beads 51 discussedabove with regard to FIGS. 9-11. The materials and dimensions oflongitudinal member 68 can be similar to those of elongated longitudinalmember 62 discussed above with respect to FIGS. 12 and 13.

FIGS. 16-19 schematically depict a procedure whereby an intracorporealspace filling device 70 is deployed within an intravascular cerebralaneurysm 71 of a patient by percutaneous means through a lumen 72 of amicrocatheter 73. The distal end 74 of microcatheter 73 is advanced overa guidewire 75 through a patient's vasculature and artery 76 to ananeurysm 71. The space filling device 70 is then distally advancedwithin an inner lumen 72 of the microcatheter 73, preferably by means ofa delivery system 77. Delivery system 77 has an elongate shaft 80 with adetachment mechanism 81 disposed on the distal end 82 of the system. Thedetachment mechanism 81 is detachably secured to a first end 83 of thespace filling device 70 which allows proximal manipulation of thedelivery system 77 to control axial advancement and retraction of thespace filing device within the microcatheter 73 and the patient. Thespace filling-device 70 is then distally advanced out of a port 84 inthe distal end 74 of the microcatheter 73 and into the aneurysm 71.

When the space filling device 70 is appropriately positioned,transmutable material of device 70 is transmuted to a rigid state, andthe space filling device 70 detached from the delivery system 77.Transmutation of the transmutable material may take place prior to,during or after detachment of the space filling device from thedetachment mechanism. The space filling device 70 is detached bydegradation of a polymer link 85 between the delivery system 77 and thefirst end 83 of the space filling device, preferably by a chain cleavagereaction which can be initiated by heating of the polymer link 85.Although the illustrated method of detachment of the space fillingdevice 70 is chain cleavage degradation of a polymer link 85, anysuitable detachment, electrolytic detachment, shape memory metal orpolymer activation via a temperature change by application of RF energy,laser energy, ultrasonic energy, heating of a hot meld adhesive joint,ultrasonic joint degradation, hydokinetic activation of a mechanicalretaining device, and the like. Various detachment mechanisms known inthe art are discussed in U.S. Pat. No. 5,722,989, J. Fitch et al., U.S.Pat. No. 5,018,407, G. Geremia et al., U.S. Pat. No. 5,217,484, M.Marks, and U.S. Pat. No. 5,423,829, P. Pham, which are herebyincorporated by reference.

Upon proper positioning of the space filling device 70 within theaneurysm 71, the device will assume a space filling folded or convolutedconfiguration due to the confinement of the aneurysm cavity, a secondaryshape imparted to the device by an elongated longitudinal member havinga secondary shape, or both of these. As a result of the folded orconvoluted configuration of the space filling device, contact points 78as shown in the enlarged view of FIG. 18A will result. Upontransmutations of the transmutable material of the device 70, contactpoints 78 cross-link, bond, self adhere or the like to become attachmentpoints which result in a more stable and rigid-transmuted space fillingdevice than would result without such attachment points. Such aconfiguration resists compaction and repositioning after deployment, andfacilitates use in aneurysms or other bodily cavities having a dome toneck ratio of less than 2 to 1. It is believed that upon properdeployment of the space filling device of the present invention, flow ofblood throughout the aneurysm will be sufficiently reduced for asufficient time to allow clot formation within the aneurysm cavity.Eventually, the clot will organize and endothelial growth over the clotin the neck area of the filled aneurysm will ensue, completing thehealing process. The resistance to compaction and reforming by the spacefilling device of the present invention is believed to facilitate thereduction of blood flow throughout the aneurysm for a sufficient timefor this healing process to occur.

As shown in FIG. 19, a blocking balloon 86 may be deployed adjacent theneck 87 of aneurysm and distal end 74 of the microcatheter 73 prior todistally advancing the space filling device from the distal end of themicrocatheter into the aneurysm. The blocking balloon 86 facilitatesmaintaining the space filling device 70 within the aneurysm 71 prior totransmutation of the transmutable material within the space fillingdevice. In this way, aneurysms having a greater neck to dome ratio canbe effectively treated.

FIG. 20 shows a distal end 90 of a delivery system 91 detachably securedto a first end 92 of a space filling device 93 having features of theinvention. The distal end 90 of the delivery system has an elongatetubular shaft 94 with an inner lumen 95 disposed therein. A detachmentsignal conduit 96 is disposed within the inner lumen 95 of the shaft andis connected to a degradable polymer link 97 at a distal extremity 98 ofthe conduit. A first end 101 of an elongate longitudinal member 102 isdetachably secured to the degradable polymer link 97 to form adetachment mechanism 103. The detachment mechanism 103 can be activatedby means of a signal transmitted through the detachment signal conduit96 which degrades the polymer link and releases the space filling device93 from the delivery system 91. The polymer link 97 is preferablydegraded by a chain cleavage or scission reaction. Materials and methodssuitable for such a mechanism are discussed generally in U.S. Pat. No.5,443,495 which has been incorporated herein. The detachment signaltransmitted through the detachment signal conduit 96 is preferably aradiofrequency signal that initiates a chain cleavage reaction in thedegradable polymer link 97, however, other signals or energy deliverymay be used such as alternating or direct electric current, ultrasonicenergy, laser energy or any other form of electromagnetic radiation orthe like. The detachment signal conduit 96 may be a single, double ormultiple pole wire, coaxial cable, fiber optic, elongate ultrasonicenergy transmitter, such as a solid rod of metal, glass or composite orthe like. If a single pole wire is used, a current flow path may beestablished by the application of a conductive pad to a suitable portionof the patient's body, preferably with a highly conductive gel betweenthe conductive pad and the patient's skin. Alternatively, a conductiveneedle, such as a stainless steel 18 gauge needle, may be inserted intoa suitable site of the patient to act as a ground. These groundingtechniques may be used for any port of the invention requiring anelectric current flow path, including the heating of elongatedlongitudinal or helical members for transmutation of transmutablematerials.

FIG. 21 shows a distal end 107 of a delivery system 108 detachablysecured to a first end 109 of a space filling device 111 having featuresof the invention. The distal end 107 of the delivery system 108 has anelongate tubular shaft 112 with an inner lumen 113 disposed therein. Adetachment signal conduit 114 is disposed within the inner lumen 113 ofthe shaft 112 and is connected to a degradable polymer link 115 at adistal extremity 116 of the conduit. The first end 109 of the spacefilling device 111 is detachably secured to the degradable polymer link115 to form a detachment mechanism 118. The detachment mechanism 118 canbe activated by means of a signal transmitted through the detachmentsignal conduit 114 which degrades the polymer link 115 and releases thespace filling device 111 from the delivery system 108. The detachmentsignal transmitted through the detachment signal conduit 114 ispreferably a low voltage direct current electric signal that heats aresistive element 119 and initiates a chain cleavage reaction in thedegradable polymer link 115. However, other signals or energy deliverymay be used such as alternating or direct electric current, ultrasonicenergy, laser energy or any other form of electromagnetic radiation orthe like. The detachment signal conduit 114 may be a single, double ormultiple pole wire, coaxial cable, fiber optic, elongate ultrasonicenergy transmitter, such as a solid rod of metal, glass or composite orthe like.

FIG. 22 shows a distal end 121 of a delivery system 122 detachablysecured to a first end 123 of a space filling device 124 having featuresof the invention. The distal end 121 of the delivery system has anelongate tubular shaft 125 with an inner lumen 126 disposed therein. Adetachment signal conduit 127 is disposed within the inner lumen 126 ofthe shaft 125 and is connected to a mechanical capture device 128 at adistal extremity 129 of the conduit. A first extremity 131 of anelongate longitudinal member 132 has an enlarged portion 133 which ismechanically captured by a plurality of capture elements 135 of themechanical capture device 128. The capture elements 135 can be activatedby means of a signal transmitted through the detachment signal conduit127 which causes the capture elements 135 to expand in an outward radialdirection which releases the enlarged portion 133 of the elongatedlongitudinal member 132 and releases the space filling device 124 fromthe delivery system 122. The detachment signal transmitted through thedetachment signal conduit is preferably a low voltage electrical signalthat heats the capture elements 135 which are made of a shape memoryalloy such as NiTi and which are configured to have a remembered shapein an open expanded position which results upon heating of the elements.A similar result can be achieved in an alternative embodiment of amechanical capture device which has capture elements which are radiallyconstrained by an elongated tubular detachment signal conduit. Uponlongitudinal retraction of the tubular conduit, the constraint of thecapture elements is removed and an enlarged portion released.Alternative detachment signals include alternating or direct electriccurrent, ultrasonic energy, laser energy or any other form ofelectromagnetic radiation or the like. The detachment signal conduit maybe a single, double or multiple pole electrically conducting wire,coaxial cable, fiber optic, elongate tubular member with an inner lumenfor conduction of hydrokinetic energy and activation of a hydrokineticdetachment mechanism, elongate ultrasonic energy transmitter, such as asolid rod of metal, glass or composite or the like. The detachmentsignal may also be in the form of mechanical actuation by longitudinalor rotational translation of a mechanical detachment signal conduit suchas an elongate rod, shaft, or tubular member.

FIG. 23 shows a distal end 138 of a delivery system 139 detachablysecured to a first end 141 of a space filling device 142 having featuresof the invention. The distal end 138 of the delivery system has anelongate tubular shaft 143 with an inner lumen 144 disposed therein. Adetachment signal conduit 145 is disposed within the inner lumen 144 ofthe shaft 143 and is connected to a mechanical capture device 146 at adistal extremity 147 of the conduit. A first extremity 148 of anelongate longitudinal member 149 has an enlarged portion 151 which ismechanically captured by a helical capture element 152 of the mechanicalcapture device 146. The helical capture element 152 can be activated bymeans of a signal transmitted through the detachment signal conduit 145which causes the capture element 152 to expand in an outward radialdirection which releases the enlarged portion 151 of the elongatedlongitudinal member 149 and releases the space filling device 142 fromthe delivery system 139. The detachment signal transmitted through thedetachment signal conduit 145 is preferably a low voltage electricalsignal that heats the capture element 152 which is made of a shapememory alloy such as NiTi and which is configured to have a rememberedshape in an open expanded position which results upon heating of theelement. Alternative detachment signals include alternating or directelectric current, ultrasonic energy, laser energy or any other form ofelectromagnetic radiation or the like. The detachment signal conduit 145may be a single, double or multiple pole wire, coaxial cable, fiberoptic, elongate ultrasonic energy transmitter, such as a solid rod ofmetal, glass or composite or the like.

An alternative capture element for the mechanical capture device couldinclude a tubular member, preferably in the form of a braided captureelement 160 as shown in FIGS. 24-26. The braided capture element 160 asshown is constructed of braided elongated filaments 161 of a shapememory alloy, such as NiTi alloy. The capture element 160 could also bea tubular member of shape memory polymer with similar properties. Theelongated filaments 161 are arranged in a braided tubular structure witha first inner diameter 162 which is smaller than a nominal diameter ortransverse dimension of an enlarged portion 163, and which mechanicallysurrounds and captures the enlarged portion. The braided tubularstructure of the capture element also has a second remembered innerdiameter 171 or transverse dimension which is greater than thetransverse dimension of the enlarged portion 163. In this way, the spacefilling device 168 can be introduced into a desired area of a patientwhile secured to a distal end 165 of a delivery system 164 by themechanical pressure of the first inner diameter 162 of the braidedcapture element 160 on the enlarge portion 163 of the first end 166 ofthe elongated longitudinal member 167 of the space filling device 168.Upon placement of the space filling device 168 within the desired areawithin a patient, the shape memory elongated filaments 161 can beactivated so as to remember the larger second inner diameter 171releasing the enlarged portion and the space filling device into thedesired area of the patient as indicated by arrow 172. Activation of thebraided capture element 160 could be carried out by the application ofenergy by the various methods described above. Such an embodiment of thecapture element, as well as any other embodiment of the capture elementdiscussed above, could be used to detach any of the various embodimentsof the space filling device discussed herein.

While particular forms of the invention have been illustrated anddescribed, it will be apparent that various modifications can be madewithout departing from the spirit and scope of the invention.Accordingly, it is not intended that the invention be limited, except asby the appended claims.

1. An intracorporeal space filling system comprising a space fillingdevice having an elongated longitudinal member and a transmutablematerial disposed about the elongated longitudinal member and beingtransmutable from a non-rigid state to a substantially rigid statewithin a patient's body, and a delivery system having an elongate shaftwith a distal end and a proximal end and a detachment mechanism disposedon the distal end of the elongate shaft and the first end of the spacefilling device detachably secured to the detachment mechanism.